Benign mass lesions deep inside the temporal bone: imaging diagnosis for proper management.

Conclusion: Among mass lesions inside the temporal bone, benign tumors and cholesteatomas can be differentiated by contrast enhancement in T1-weighted images (T1WI) and by diffusion-weighted images (DWI). Moreover, DWI will also facilitate discrimination between cholesteatomas accompanied by granulation and other non-neoplastic lesions such as mucoceles and cholesterol granulomas.

Objectives: To review the imaging characteristics of mass lesions inside the temporal bone and to investigate pertinent imaging modalities for differential diagnosis, which is crucial for appropriate treatment planning.

Patients and methods: This was a retrospective case series study of six patients seen between 2002 and 2005 with mass lesions deep inside the temporal bone.

Results: One patient had facial schwannoma, two had glomus jugulare tumor, and three had cholesteatoma. Plain high resolution CT gave few clues to the nature of the mass lesions. MRI study provided us with better clues: contrast enhancement on T1WI was observed only in benign tumors and only cholesteatomas showed high intensity on DWI. With the assistance of neurosurgeons, surgery was successfully performed in all cases.